The Heathrow Express is the quickest and easiest way for business travellers to scoot between Heathrow Airport and London city, or at least Paddington Station – which is a decent place to settle in your hotel (I'm a fan of the hip little Hotel Indigo, just a few minutes' walk away on London Street) or hop a Tube train or an Uber to your final destination.
But for some top-tier frequent flyers, even that fast 15 minute ride can be enjoyed in the relative comfort of the train's 'Business First' first class cabin via a free upgrade from the more crowded standard 'Express' carriages.
Located at either end of the Heathrow Express, these swish carriages offer a little more legroom than in a regular 'economy' carriage, plus wider seats in a more relaxed 1-1 layout, a personal table and even an AC power socket at each seat in case your device needs a fast top-up.
They're also less crowded and therefore quieter than regular carriages. So what's the trick to getting a free first class bump on the Heathrow Express?
You'll need to hold Star Alliance Gold status with any Star Alliance airline, or the more exclusive Gold Guest List card with British Airways Executive Club.
The Heathrow Express Business First upgrade for Star Alliance Gold status
This one's a doddle for frequent business travellers, as it covers the Gold-equivalent tiers of Singapore Airlines, United Airlines, ANA, Thai Airways, Asiana, Air New Zealand, Lufthansa and Swiss, among others.
Purchase a standard Heathrow Express ticket, but make your way to the Business First carriage and settle in. When the conductor passes through, simply show your ticket and your Gold frequent flyer card (or smartphone app).
The Heathrow Express Business First upgrade for BAEC GGL status
British Airways Executive Club Gold Guest List (GGL) status is a loftier reach than Star Alliance Gold, sitting level above BAEC Gold – which is on par with Qantas Platinum and other Oneworld Emerald tiers.
However, unlike the Star Alliance Gold upgrade, having a BAEC GGL card also lets you upgrade a guest travelling with you on the Heathrow Express.
Just buy a standard Heathrow Express ticket, plonk yourself in the Business First carriage and show the conductor your ticket and your BAEC Gold Guest List card or or smartphone app.
Note that the free Heathrow Express first class upgrade applies only to BAEC Gold Guest List members – not BAEC Gold or other Oneworld Emerald-grade frequent flyers.